1. Field of the Invention
The present invention relates to a keyboard with a key lock function, for supplying signals to an information processing device such as a personal computer through key button actions.
2. Description of the Prior Art
Some keyboards electrically connected to information processing devices have a key lock function for preventing the keyboard from supplying signals to the information processing device even when key buttons are undesirably pressed for some reason while the information processing device is being turned on and not attended by the operator. The key lock function is effective to prevent stored data in the information processing device from being eliminated or broken, for example, through unintentional key button actions.
Known keyboards with a key lock function are disclosed in Japanese laid-open utility model publication No.76630/1989 and Japanese laid-open patent publication No. 268024/1988 for example.
The keyboard disclosed in Japanese laid-open utility model publication 76630/1989 has a key lock switch mounted on the upper surface thereof, the key lock switch being pressable downwardly. When the key lock switch is pressed downwardly by the operator, the keyboard enters a lock mode.
The keyboard disclosed in Japanese laid-open patent publication No. 268024/1988 includes logic circuit 5 disposed below and connected to switching part 3 (key lock switch) and keyboard circuit 1 for entering signals. Insofar as the logic circuit is supplied with a lock mode signal from the key lock switch, the logic circuit does not deliver a signal to the central processing circuit 6 (an information processing device) even when a key button is pressed to supply a key signal.
With the keyboard disclosed in Japanese laid-open utility model publication No.76630/1989, since the key lock switch is a pressable switch mounted on the upper surface of the keyboard, when the key lock switch is inadvertently pressed, the keyboard changes from the lock mode to an unlock mode against the will of the operator.
Japanese laid-open patent publication No.268024/1988 is silent about the type and layout of the key lock switch in the switching part. Since the disclosed keyboard needs the logic circuit, the keyboard is complex in structure and susceptible to a higher failure rate, and tends to suffer a high manufacturing cost.